21st Century C-1000 Prolonged Release Caplets - Long-Lasting Immune and Antioxidant Support. ‣ Prolonged release for sustained vitamin C benefits. ‣ Boosts immune system function. ‣ Powerful antioxidant protection. ‣ Supports skin health and collagen production. SUGGESTED USE: Take one caplet daily with any meal, or as directed by your healthcare provider. INGREDIENTS: Vitamin C (as Ascorbic Acid)